dt-bindings: iio/adc: qcom,spmi-iadc: use double compatibles

As in other bindings, let's use specific compatibles together with the
fallback compatible. Adjust the bindings for it.
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221031182456.952648-1-luca@z3ntu.xyzSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.yaml

@@ -18,7 +18,10 @@ description: |
 
 properties:
   compatible:
-    const: qcom,spmi-iadc
+    items:
+      - enum:
+          - qcom,pm8941-iadc
+      - const: qcom,spmi-iadc
 
   reg:
     description: IADC base address and length in the SPMI PMIC register map
@@ -50,7 +53,7 @@ examples:
         #address-cells = <1>;
         #size-cells = <0>;
         pmic_iadc: adc@3600 {
-            compatible = "qcom,spmi-iadc";
+            compatible = "qcom,pm8941-iadc", "qcom,spmi-iadc";
             reg = <0x3600>;
             interrupts = <0x0 0x36 0x0 IRQ_TYPE_EDGE_RISING>;
             qcom,external-resistor-micro-ohms = <10000>;